Member some local I'm backing (4)
I believe the answer is:
limb
'member' is the definition.
(limb is a kind of member)
'some local i'm backing' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'LIMB' can be found hidden inside 'local im backing'.
(Other definitions for limb that I've seen before include "Substantial branch from a tree trunk" , "Arm, leg or wing" , "Jointed appendage" , "Human's extension" , "Wing, perhaps" .)